1. Field of the Invention
This invention relates to a clutch disk and, more particularly, to a split hub type clutch disk.
2. Description of the Prior Art
Split hub type clutch disk is well known in the art in which a hub flange is split into inner and outer flanges. This type of clutch disk is composed of a hub to be coupled with a torque output shaft, an inner hub flange fixed integrally to the hub, an outer hub flange disposed concentrically on the outside of the inner hub flange so that it can rotate within the extent of a predetermined angle by means of splines with respect to the inner hub flange, main and auxiliary disk plates disposed on each side of both the flanges which are to be coupled with a torque input shaft, and hysteresis means including thrust material provided between the flanges and the main and auxiliary disk plates.
According to such a configuration as above, since the thrust material of the hysteresis means covers the spline sections of the inner and outer hub flanges, it is in friction engagement with the sides of the spline teeth. Hence, friction surfaces are created on the respective sides of the inner and outer hub flanges, but, it is uncertain on which of the inner and outer hub flanges the thrust material slides, thus, the hysteresis of the torque transfer characteristic of the clutch disk is unstable. Further, since the thrust material is scratched by the edges of the spline teeth, this makes the hysteresis more unstable.